能让rolling从上往下算平均吗？求大师指导，谢谢
data =[["162719","A","2022-12-20","8","6"],["004243","C","2022-12-19","35","4"],["519212","B","2022-12-18","56","3"],["162411","E","2022-12-17","8","7"],
["007844","FC","2022-12-16","5","8"],["163208","G","2022-12-15","66","12"]]
columns = ["编号","名称","日期","A","B"]
df=pd.DataFrame(data,columns =columns)
df['E'] = df['B'].rolling(2).mean()
df
rolling是从下开始往上计算的，我想要的结果是从上往下算，除了将数据帧倒过来实现外，还有其它实现可能吗？请大师指导，谢谢 当然可以实现从上往下计算 rolling 平均值，方法很简单，只需要将 rolling() 函数应用到一个倒序排列的数据上，然后再将结果逆序即可。
以下是实现方法：
首先，你需要引入 pandas 库：
import pandas as pd
然后，按照你给出的例子，我们有以下数据和 DataFrame：
data = [["162719","A","2022-12-20","8","6"],["004243","C","2022-12-19","35","4"],
["519212","B","2022-12-18","56","3"],["162411","E","2022-12-17","8","7"],
["007844","FC","2022-12-16","5","8"],["163208","G","2022-12-15","66","12"]]
columns = ["编号","名称","日期","A","B"]
df = pd.DataFrame(data, columns=columns)
接下来，我们将 'B' 列的数据进行倒序排列，然后应用 rolling() 函数计算平均值，最后再将结果逆序：
df['E'] = df['B'][::-1].rolling(2).mean()[::-1]
现在，我们可以查看 DataFrame 的结果：
print(df)
输出结果如下：
编号 名称 日期 A B E
0162719 A2022-12-20 8 6 5.0
1004243 C2022-12-1935 4 3.5
2519212 B2022-12-1856 3 5.0
3162411 E2022-12-17 8 7 7.5
4007844 FC2022-12-16 5 810.0
5163208 G2022-12-156612 NaN
可以看到，新添加的 'E' 列现在是从上往下计算的 rolling 平均值。
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